For generating a stabilized DC output voltage, more and more switching regulators are used for DC-DC conversion, because of the high efficiency of the switching power supplies. New equipment designs and low parts costs with a simple design make the use of switching regulators more pronounced over that of linear regulators. A further advantage of a switching regulator is the increased application flexibility of the output voltage, which can be less than, greater than, or of opposite polarity to that of the input voltage.
When using a monolithic control circuit as a driver circuit for a switching transistor, only a few circuit parts are required for designing a DC-DC converter. Control circuits of this kind comprise an internal temperature compensated reference voltage, a comparator, a controlled duty cycle oscillator with an active current limit circuit, a driver stage and a high current output switch. A known monolithic control circuit of this kind is for example the integrated circuit MC34063 manufactured by ON Semiconductor Components Industries and Unisonic Technologies Co, or the integrated circuit μA78S40.